Tonatia bidens - Greater Round-eared Bat​

Physical Description:

Tonatia bidens (Greater Round-eared Bat) is a medium sized bat and a member of the family Phyllostomidae.  The family Phyllostomidae includes 143 species of bats placed in 49 genera, within the genus Tonatia there are currently seven species recognized (Animal Diversity Web, Porter 2003).  Many phyllostomids have a relatively simple spear shaped noseleaf, also they lack postorbital processes and their premaxillae are complete and fused to each other and to the maxillae (Animal Diversity Web).  Tonatia bidens is considered at times to be rare and little biology of the species is known (Esberard 2004).  A majority of authors recognize a single genus (Tonatia) for the round-eared bats, but several studies imply that the Tonatia bidens complex is divergent from the other round eared bats (Porter 2003).

Distribution:

Tonatia bidens occurs from southern Mexico, south to Peru, and east to northeast Brazil  (Lee 2002, Esberard 2004).  Specific countries of occurrence are Argentina, Brazil, Bolivia, Paraguay, and Peru (InfoNatura 2003).  Within Paraguay Tonatia bidens is mainly located in the west, in the Alto Chaco region (Willig 2000).  In general the genus Tonatia is a widespread, Neotropical group (Lee 2002).

Ontogeny and Reproduction:

The females of Tonatia bidens have been observed pregnant in November and nursing in May.  Sub-adult bats have been observed in December, February, May, and July (Esberard 2004).

Ecology and Behavior:

Tonatia bidens is considered to be both frugivorous and insectivorous.  Birds have also been known to have been preyed upon by Tonatia bidens.  Insects such as, Orthoptera, Coleoptera, Odonata, and Lepidopteria comprise some of the bats insect diet.  Bird species that are lighter than Tonatia bidens itself were most commonly taken (Martuscelli 1995).  Tonatia bidens use themselves, hollows of trees, caves, or abandoned houses for shelter, forming small groups (Esberard 2004, Martuscelli 1995).

Remarks:

Opossums were at one time valued for their fur, which was used to make cuffs and collars for jackets and coats.  They are still trapped by some and eaten although they are not regarded as a prime source of nutrition.  They are hunted primarily in the southern U.S. at night with the aide of hounds and spotlights (Lyon 1936).

Literature Cited:

Animal Diversity Web.  1999.  “Phyllostomidae” (On-line), Accessed October 27, 2004 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Phyllostomi-dae.html.

Esberard, Carlos and Bergallo, H.G.  2004.  Aspects on the Biology of Tonatia bidens (Spix) in the state of Rio De Janeiro, Southeast of Brazil (Mammalia, Chiroptera, Phyllostomidae).  Brazilian Journal of Zoology, 21(2).

InfoNatura.  Tonatia bidens – Greater Round Eared Bat.  2003. Accessed October 27, 2004 at http://www.natureserve.org/infonatura/servlet/InfoNatura?searchName=Tonatia+bidens.

Lee, Thomas E; Hoofer, S.R.; Van Den Bussche, R.A.  2002.  Molecular Phylogenetics and Taxonomic Revision of the Genus Tonatia (Chiroptera:  Phyllostomaidae).  Journal of Mammalogy, 83(1):49-57.

Martuscelli, Paulo.  1995.  Avian Predation by the Round-Eared Bat (Tonatia bidens, Phyllostomaidae) in the Brazilian Atlantic Forest.  Journal of Tropical Ecology, 11:461-464.

Porter, Calvin A; Hoofer, S.R.; Van Den Bussche, R.A; Lee, T.E. Jr.; Baker, R.J.  2003.  Systematics of Round-Eared (Tonatia and Lophostoma) Based on Nuclear and Mitochondrial DNA Sequences.  Journal of Mammalogy, 84(3): 791-808.

Willig, Michael R.; Presley, Steven J.; Owen, Robert D.; Lopez-Gonzalez, Celia.  2000.  Composition and Structure of Bat Assemblages in Paraguay:  A Subtropical – Temperate Interface.  Journal of Mammalogy, 81(2):  386-401.

Reference written Kyle Skildum, Biology 378 (Mammalogy), University of Wisconsin – Stevens Point.  Edited by Christopher Yahnke. Page last updated August 15, 2005